KR102065056B1 - Method for processing transmission signal and apparatus for the same - Google Patents

Abstract

A signal processing method performed at a communication node is disclosed. Generating a data stream based on the number of subcarriers per channel; Performing normalization and normalization reduction on the data stream based on the maximum number of subcarriers among the number of subcarriers per channel, the IFFT port size included in the communication node, and the DAC port size included in the communication node; And transmitting the reduced data stream. Therefore, the quantization error can be minimized and the influence due to the final output of the transmission signal can be minimized.

Description

Transmission signal processing method and apparatus {METHOD FOR PROCESSING TRANSMISSION SIGNAL AND APPARATUS FOR THE SAME}

The present invention relates to a method and apparatus for processing a transmission signal, and more particularly, to a method and apparatus for processing a transmission signal in an orthogonal frequency division multiplexing network.

In a cellular communication network, a user equipment may generally transmit and receive a data unit through a base station. For example, if there is a data unit to be transmitted to the second terminal, the first terminal may generate a message including the data unit to be transmitted to the second terminal and transmit the generated message to the first base station to which it belongs. Can transmit The first base station may receive a message from the first terminal, and may confirm that the destination of the received message is the second terminal. The first base station may transmit a message to the second base station to which the second terminal which is the confirmed destination belongs. The second base station may receive a message from the first base station, and may confirm that the destination of the received message is the second terminal. The second base station may transmit a message to the second terminal which is the confirmed destination. The second terminal may receive a message from the second base station, and may acquire a data unit included in the received message.

Orthogonal Frequency Division Multiplexing (OFDM) based communication among the above-described transmission / reception procedures of the data unit may be as follows.

In order to perform signal transmission, a signal occupying various bandwidths (for example, a signal occupying various numbers of subcarriers) may be input to the transmitter.

A signal occupying various bandwidths input to the transmitter may be Inverse Fast Fourier Transform (IFFT).

As a result of IFFT conversion, that is, the IFFT conversion of a signal occupying various bandwidths, that is, a time domain signal input to a digital-to-analog converter (DAC) may have various sizes. The magnitude of the time domain signal input to the DAC may be expressed in units of bits.

When the size of the signal input to the DAC and the size (or number) of the DAC input ports are the same, the signal to noise ratio (SNR) of the analog signal output from the DAC may be maximized.

In addition, when the size of the signal input to the DAC and the size of the DAC input port correspond, the quantization error of the analog signal output from the DAC may be reduced.

However, when the size of the signal input to the DAC is smaller or larger than the size of the DAC input port, the quantization error of the analog signal output from the DAC may increase. If the quantization error of the analog signal output from the DAC increases, a problem may occur that the quality of the signal is lowered.

An object of the present invention for solving the above problems is to provide a method for optimizing the quality of the DAC output transmission signal by including a normalization process between the signal output from the IFFT and the signal input to the DAC.

A signal processing method performed in a communication node according to an embodiment of the present invention for achieving the above object comprises the steps of: generating a data stream based on the number of subcarriers for each channel; The IFFT port based on the maximum number of subcarriers among the number of subcarriers for each channel, an Inverse Fast Fourier Transform (IFFT) port size included in the communication node, and a digital analog convert (DAC) port size included in the communication node. Performing normalization on the output data stream such that the size of the data stream output from the data source corresponds to the size of the DAC port; Performing reduction on the data stream output from the DAC port based on the maximum number of subcarriers and the IFFT port size; And transmitting the reduced data stream.

According to the present invention, there is an effect that the transmission signal quality is improved in the transmitter of the orthogonal frequency division multiplexing network. Specifically, when the number of DAC input ports (or the number of input bits) is relatively small (5 bits or less), and the number of subcarriers of the IFFT input is relatively small, the transmission signal quality is greatly improved.

Therefore, according to the present invention, when a cheap DAC having a relatively small number of input ports of the DAC is used, the quantization error can be minimized and the transmission signal quality can be improved.

1 is a conceptual diagram illustrating an embodiment of a communication network.
2 is a block diagram illustrating an embodiment of a communication node constituting a communication network.
Fig. 3 is a block diagram showing the first embodiment of the configuration of the transmitting and receiving device of the communication node.
4 is a block diagram showing a second embodiment of the configuration of a communication node transmission and reception apparatus.
5 is a flowchart illustrating one embodiment of a communication method in a communication network.
6 is a conceptual diagram illustrating an embodiment of a communication method in a communication network in detail.
7 is a block diagram illustrating one embodiment of a system for performing simulations of embodiments of a communication method.
8 is a graph illustrating a bit error rate when the number of subcarriers is 12 according to a conventional method.
9 is a graph illustrating a bit error rate when the number of subcarriers is 12 in the proposed method.
10 is a graph illustrating a bit error rate when the number of subcarriers is 120 according to a conventional method.
11 is a graph illustrating a bit error rate when the number of subcarriers is 120 in the proposed method.
12 is a graph illustrating a bit error rate when the number of subcarriers is 600 according to a conventional method.
13 is a graph illustrating a bit error rate when the number of subcarriers is 600 according to the proposed method.

As the present invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

When a component is said to be "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that another component may be present in the middle. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. In the following description of the present invention, the same reference numerals are used for the same elements in the drawings and redundant descriptions of the same elements will be omitted.

In the following, a wireless communication network to which embodiments according to the present invention are applied will be described. The wireless communication network to which embodiments according to the present invention are applied is not limited to the contents described below, and the embodiments according to the present invention may be applied to various wireless communication networks.

1 is a conceptual diagram illustrating an embodiment of a communication network.

Referring to FIG. 1, the communication network 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). Each of the plurality of communication nodes may support at least one communication protocol. For example, each of the plurality of communication nodes may include a code division multiple access (CDMA) based communication protocol, a wideband CDMA (WCDMA) based communication protocol, a time division multiple access (TDMA) based communication protocol, and a frequency division multiple (FDMA) based communication protocol. access based communication protocol, orthogonal frequency division multiplexing (OFDM) based communication protocol, orthogonal frequency division multiple access (OFDMA) based communication protocol, single carrier (SC) -FDMA based communication protocol, non-orthogonal multiple An access based communication protocol and a space division multiple access (SDMA) based communication protocol may be supported. Each of the plurality of communication nodes may have a structure as follows.

2 is a block diagram illustrating an embodiment of a communication node constituting a communication network.

Referring to FIG. 2, the communication node 200 may include at least one processor 210, a memory 220, and a transceiver 230 that communicates with a network. In addition, the communication node 200 may further include an input interface device 240, an output interface device 250, a storage device 260, and the like. Each component included in the communication node 200 may be connected by a bus 270 to communicate with each other.

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260. The processor 210 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured as at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory 220 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

Fig. 3 is a block diagram showing the first embodiment of the configuration of the transmitting and receiving device of the communication node.

Referring to FIG. 3, the communication node may include a transmission controller 300, a transmitter 310, a radio frequency (RF) unit 320, and the like. The transmitter 310 may include a channel generator 311, a resource mapping unit 312, an inverse fast fourier transform (IFFT) unit 313, and a digital to analog converter (DAC) 314.

The transmission controller 300 may be the processor 210 of FIG. 2. The transmitter 310 and the RF unit 320 may be the transceiver 230 of FIG. 2.

The channel generator 311 of the transmitter 310 may receive subcarrier number information for each channel from the transmission controller 300.

The channel generator 311 may generate a data stream on the basis of the subcarrier number information for each channel received from the transmission controller 300 for each transmission time interval (TTI).

The channel generator 311 may transmit the data stream to the resource mapping unit 312. The resource mapping unit 312 may receive a data stream from the channel generator 311.

The resource mapping unit 312 may map the received data stream to resources in OFDM symbol units. The OFDM symbol unit may generally be 3.2 μs. The resource mapping unit 312 may transmit the data stream mapped to the resource to the IFFT unit 313.

The IFFT unit 313 may receive a data stream mapped to a resource from the resource mapping unit 312. The IFFT unit 313 may convert the data stream mapped to the resource for each TTI from the frequency domain to the time domain (hereinafter, referred to as 'IFFT transform').

으로 표현될 수 있다.The size of the IFFT transformed data stream may be expressed in bits. For example, if the size of the IFFT converted data stream is n bits, then the size of the IFFT converted data stream is

It can be expressed as.

The IFFT unit 313 may transmit the IFFT converted data stream to the DAC 314. The DAC 314 may receive the IFFT transformed data stream from the IFFT unit 313.

The DAC 314 may perform digital to analog conversion on the IFFT transformed data stream. That is, the DAC 314 may generate an analog signal based on the IFFT transformed data stream. The DAC 314 may transmit an analog signal to the RF unit 320. The RF unit 320 may transmit an analog signal received from the DAC 314.

If the size of the data stream input to the DAC 114 and the size (or number) of the input ports of the DAC 114 are not the same, the quantization error may increase in the DAC 314 and the DAC 314 may increase. Signal to noise ratio (SNR) for the analog signal output from

Therefore, when the size of the data stream input to the DAC 114 and the size of the input port of the DAC 114 do not correspond, a problem may occur that the transmission signal quality is lowered. In the following, a transmission signal processing method in a communication network for solving the above problem may be described.

4 is a block diagram showing a second embodiment of the configuration of a communication node transmission and reception apparatus.

Referring to FIG. 4, the communication node may include a transmission controller 400, a transmitter 410, an RF unit 420, and the like. The transmitter 410 may perform the channel generator 411, the resource mapping unit 412, the IFFT unit 413, the normalization unit 414, the DAC 415, the normalization reduction unit 416, and the bandwidth calculation unit 417. It may include.

The transmission control unit 400 may be the processor 210 of FIG. 2. The transmitter 410 and the RF unit 420 may be the transceiver 230 of FIG. 2.

In FIG. 4, a normalization unit 414, a normalization reduction unit 416, and a bandwidth calculation unit 417 may be additionally included in the configuration of FIG. 3. The functions of the normalization unit 414, the normalization reduction unit 416, and the bandwidth calculation unit 417 may be described in detail with reference to FIG. 5.

5 is a flowchart illustrating one embodiment of a communication method in a communication network.

Referring to FIG. 5, the transmission controller 400 may transmit the subcarrier number information for each channel to the channel generator 411 of the transmitter 410. The subcarrier number information for each channel may indicate information on occupied bandwidth for each channel.

The channel generator 411 of the transmitter 410 may receive subcarrier number information for each channel from the transmitter controller 400 (S500).

The bandwidth calculator 417 may receive subcarrier number information for each channel from the transmission controller 400. The bandwidth calculator 417 may store 'maximum number of subcarriers' information having the maximum number of subcarriers per channel based on the received number of subcarriers per channel.

The bandwidth calculator 417 may transmit the maximum subcarrier number information to the normalization unit 414 and the normalization reduction unit 416. The maximum subcarrier number information may be used in the normalization process in the normalization unit 414. The maximum subcarrier number information may be used in the normalization reduction process in the normalization reduction unit 416.

The channel generator 411 of the transmitter 410 may receive subcarrier number information for each channel from the transmitter controller 400.

The channel generator 411 may generate a data stream based on the subcarrier number information for each channel received from the transmission controller 400 for each TTI (S510).

The channel generator 411 may transmit the data stream to the resource mapping unit 412. The resource mapping unit 412 may receive a data stream from the channel generator 411.

The resource mapping unit 412 may map the received data stream to resources in OFDM symbol units (S520). The resource mapping unit 412 may transmit the data stream mapped to the resource to the IFFT unit 413.

The IFFT unit 413 may receive a data stream mapped to a resource from the resource mapping unit 312. The IFFT unit 413 may IFFT transform the data stream mapped to the resource for each TTI (S530).

Specifically, the IFFT transform may be as follows.

6 is a conceptual diagram illustrating an embodiment of a communication method in a communication network in detail.

Referring to FIG. 6, the number of subcarriers input to the IFFT unit 413 may be 1/4, 1/2, or 3/4 times the size of the input port included in the IFFT unit 413.

The IFFT unit 413 may perform an IFFT transformation for converting a data stream mapped to a resource from a frequency domain to a time domain. The size of the IFFT transformed data stream may be obtained by the following equation.

In this case, ifft (x) may be a function related to IFFT transformation for converting a data stream mapped to a resource from a frequency domain to a time domain. The IFFT transformed data stream may be configured in OFDM symbol units.

을 포함하고 있을 수 있다. 따라서

을 곱해줌으로써 IFFT 변환된 데이터 스트림의 크기를 조정할 수 있다. IFFT_SIZE는 IFFT부(413)에 포함된 입출력 포트 크기를 지시할 수 있다.ifft (x) is

It may include. therefore

You can adjust the size of the IFFT transformed data stream by multiplying by. IFFT_SIZE may indicate the input / output port size included in the IFFT unit 413.

으로 표현될 수 있다.The size of the IFFT transformed data stream may be expressed in bits. For example, if the size of the IFFT converted data stream is n bits, then the size of the IFFT converted data stream is

It can be expressed as.

Referring back to FIG. 5, the IFFT unit 413 may transmit the IFFT-converted data stream to the normalization unit 414. The normalizer 414 may receive the IFFT transformed data stream from the IFFT unit 413.

The normalizer 414 uses the maximum subcarrier number information received from the bandwidth calculator 417 and the size of the IFFT transformed data stream received from the IFFT unit 413 for each TTI to determine the data stream input to the DAC 415. Normalization of matching the size to the size of the DAC input port may be performed (S540).

Specifically, the normalization process may be as follows.

Referring back to FIG. 6, the normalization process of the IFFT transformed data stream may be expressed by the following equation.

으로 표현될 수 있다.y may be the size of the IFFT transformed data stream. y can be expressed in bits. For example, if the size of the IFFT converted data stream is n bits, then the size of the IFFT converted data stream is

It can be expressed as.

The normalization unit 414 may adjust the size of the data stream so that the size of the IFFT transformed data stream matches the size of the IFFT input / output port.

The normalizer 414 may perform rounding to adjust the size of the data stream input to the DAC 415 to match the size of the DAC input port. The size and rounding of the data stream to fit the size of the IFFT input and output ports may be included in the normalization process.

Rounding may be performed by the following equation.

Z may indicate the size of the rounded data stream to fit the size of the DAC input port. The normalizer 414 may obtain a normalized data stream having a size z of the data stream.

Here, the number of IFFT output bits may indicate that the output port size included in the IFFT 413 is expressed in bit units. The number of DAC input bits may indicate that the input port size of the DAC 415 is expressed in bits.

일 수 있다. For example, if the number of I / O bits is n bits, the I / O port size is n squared of two.

Can be.

Referring back to FIG. 5, the DAC 415 may receive a data stream normalized to fit the DAC input port size.

The DAC 415 may perform DAC conversion of the normalized data stream received from the normalization unit 414 for each TTI (S550). The DAC 415 may obtain a DAC converted analog signal through DAC conversion of the normalized data stream.

The DAC 415 may transmit the DAC-converted analog signal to the normalization reduction unit 416. The normalization reduction unit 416 may receive a DAC converted analog signal.

The normalization reduction unit 416 may receive the maximum subcarrier number information from the bandwidth calculator 417. The normalization reduction unit 416 may perform normalization reduction to reduce the size of the signal that was adjusted in the normalization process of the DAC-converted analog signal (S560).

Specifically, the normalized reduction process may be as follows.

Referring back to FIG. 6, the normalization reduction unit 416 may perform normalization reduction of the DAC converted data stream. Normalized reduction may be performed by the following equation.

The normalization reduction unit 416 may use the maximum subcarrier number information received from the bandwidth calculator 417 for normalization reduction for each TTI.

의 역수인

을 DAC 변환된 아날로그 신호에 곱할 수 있다.The normalization reduction unit 416 multiplies in the normalization process

An inverse of

Can be multiplied by the DAC converted analog signal.

The normalization reduction unit 416 may obtain a reduced analog signal having a reduced size through a normalization reduction process.

Referring back to FIG. 5, the normalization reduction unit 416 may transmit the reduced analog signal to the RF unit 420. The RF unit 420 may transmit an analog signal received from the reducing unit 416.

7 is a block diagram illustrating one embodiment of a system for performing simulations of embodiments of a communication method.

Referring to FIG. 7, the normalization reduction unit 416 may transmit the reduced analog signal to the FFT unit 710.

The reduced data stream may include Additive White Gaussian Noise (AWGN) 700. AWGN may be noise with a normal distribution. The normalization reduction unit 416 may transmit the reduced analog signal including the noise to the FFT unit 710.

The channel generator 411 may transmit the data stream to the uncoded bit error rate (uncoded BER) calculator 750.

The FFT unit 710 may transmit the reduced analog signal including the noise to the equalizer 720 and the channel estimator 730. The channel estimator 730 may receive a reduced analog signal including noise and perform channel estimation.

The channel estimator 730 may transmit the channel estimated analog signal to the equalizer 720. The equalizer 720 may indicate an apparatus for adjusting the received signal by adjusting the relative strength of each signal including various frequency bands.

The equalizer 720 may emphasize or decrease a specific frequency band. The equalizer 720 may transmit the strength adjusted analog signal to a hard decision 740.

Hard decision 740 may distinguish between 0 and 1 in the intensity adjusted data stream. Hard decision 740 may indicate a device having the ability to distinguish between zero and one from the intensity adjusted data stream. The hard decision 740 may transmit an analog signal separated by 0 and 1 to the bit error calculator 750.

The bit error rate calculator 750 may calculate the bit error rate based on the subcarrier number information for each channel received from the channel generator 411 and a data stream in which 0s and 1s are separated from the hard decision 740. .

The bit error rate measurement simulation of the present invention for checking the transmission signal quality may include a normalization unit 414 and a normalization reduction unit 416. The simulation of the present invention can be performed by measuring the bit error rate when the transmission signal, i.e., the analog signal contains noise.

The conventional bit error rate measurement simulation for checking the transmission signal quality may not include the normalization unit 414 and the normalization reduction unit 416 in the configuration of FIG. 7. That is, conventional simulation can be performed by measuring the bit error rate without normalization and normalization reduction.

8 to 13 may be a result of measuring the bit error rate by fixing the input / output port size of the IFFT unit 413 to 1024.

8 is a graph illustrating a bit error rate when the number of subcarriers is 12 according to a conventional method.

9 is a graph illustrating a bit error rate when the number of subcarriers is 12 in the proposed method.

8 and 9, the vertical axis of the graph may indicate a bit error rate. The horizontal axis of the graph may indicate signal to noise ratio in digital communication as energy per bit to noise power spectral density ratio (Eb / No).

The graph of FIG. 8 may be a result of experimenting with a conventional method that does not include the normalization unit 414 and the normalization reduction unit 416 in the configuration of FIG. 7. 9 may be a result of experimenting with the proposed method including the normalization unit 414 and the normalization reduction unit 416 in the configuration of FIG. 7.

If the number of DAC input bits is 4 bits, the DAC input port size may be 16, which is a power of two. If the number of DAC input bits is 5 bits, the size of the DAC input port may be 32, which is a power of two.

If the number of DAC input bits is 6 bits, the DAC input port size may be 64, which is a power of two. When the number of DAC input bits is 7 bits, the size of the DAC input port may be 128, which is a power of two.

If the number of DAC input bits is 8 bits, the DAC input port size can be 256, which is power of two.

This graph may be a result of experimenting with the number of subcarriers as 12 and increasing the number of DAC input bits from 4 to 8. When the number of DAC input bits is 5 bits or less, it can be confirmed that the graph of FIG. 9, in which the experiment is performed in the proposed method, has a lower bit error rate than the graph of FIG. 8.

10 is a graph illustrating a bit error rate when the number of subcarriers is 120 according to a conventional method.

11 is a graph illustrating a bit error rate when the number of subcarriers is 120 in the proposed method.

10 and 11, the vertical axis of the graph may indicate a bit error rate. The horizontal axis of the graph is Eb / No, which may indicate a signal-to-noise ratio in digital communication.

The graph of FIG. 10 may be a result of experimenting with a conventional method that does not include the normalization unit 414 and the normalization reduction unit 416 in the configuration of FIG. 7. The graph of FIG. 11 may be a result of experimenting with the proposed method including the normalization unit 414 and the normalization reduction unit 416 in the configuration of FIG. 7.

This graph may be a result of experimenting with the number of subcarriers as 120 and increasing the number of DAC input bits from 4 to 8. When the number of DAC input bits is 4 bits or less, it can be confirmed that the graph of FIG. 11, in which the experiment is performed in the proposed method, has a lower bit error rate than the graph of FIG. 10.

12 is a graph illustrating a bit error rate when the number of subcarriers is 600 according to a conventional method.

13 is a graph illustrating a bit error rate when the number of subcarriers is 600 according to the proposed method.

12 and 13, the vertical axis of the graph may indicate a bit error rate. The horizontal axis of the graph is Eb / No, which may indicate a signal-to-noise ratio in digital communication.

The graph of FIG. 12 may be a result of experimenting with a conventional method that does not include the normalization unit 414 and the normalization reduction unit 416 in the configuration of FIG. 7. 13 may be a result of experimenting with the proposed method including the normalization unit 414 and the normalization reduction unit 416 in the configuration of FIG. 7.

This graph may be a result of experimenting with the number of subcarriers as 12 and increasing the number of DAC input bits from 4 to 8. When the number of DAC input bits is 4 bits or less, it may be confirmed that the graph of FIG. 13, in which the experiment is performed in the proposed method, has a lower bit error rate than the graph of FIG. 12.

The methods according to the invention can be implemented in the form of program instructions that can be executed by various computer means and recorded on a computer readable medium. Computer-readable media may include, alone or in combination with the program instructions, data files, data structures, and the like. The program instructions recorded on the computer readable medium may be those specially designed and constructed for the present invention, or may be known and available to those skilled in computer software.

Examples of computer readable media include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention described in the claims below. Could be.

Claims (12)

In a communication node,
An IFFT unit for transforming a data stream into an inverse fast fourier transform (IFFT) for each transmission time interval;
A normalizer for normalizing the IFFT-converted data stream based on the maximum subcarrier number information for each channel and the size of the IFFT-converted data stream;
A digital analog converter for converting the normalized data stream into an analog signal;
A normalization reduction unit for reducing the data stream converted into the analog signal based on the maximum number of subcarriers per channel and the size of the IFFT converted data stream; And
A radio frequency (RF) unit for transmitting the reduced data stream;
The normalizer performs a normalization operation in inverse proportion to the maximum number of subcarriers for each channel and proportional to the size of the IFFT transformed data stream,
Performing a rounding operation to match the size of the data stream to the size of an input port of the digital-to-analog converter based on the following equation,

Z denotes a normalized data stream adjusted to correspond to an input port size of the digital analog converter, y denotes a normalized data stream proportional to the size of the IFFT converted data stream, and OUT _IFFT is An output port size of the IFFT unit, and the IN _DAC indicates an input port size of the digital to analog converter. The method according to claim 1,
The size of the data stream input to the IFFT unit is different from the size of the input port of the digital to analog converter. delete The method according to claim 1,
The normalization unit,
Generate a normalized data stream proportional to the size of the IFFT transformed data stream based on the following equation,

The y indicates the normalized data stream, the DS _IFFT indicates a data stream obtained from the IFFT unit, the S _IFFT indicates an input / output port size of the IFFT unit, and N _max indicates a subcarrier for each channel. Indicating the maximum number of nodes. delete The method according to claim 1,
The normalized reduction unit,
Generate the reduced data stream based on the following equation,

The DS _RE indicates the reduced data stream, the DS _DAC indicates a data stream output from the digital analog converter, and the S _IFFT indicates an input / output port size of the IFFT unit. In the method of operation of the communication node,
IFFT transforming the data stream for each transmission time interval through an inverse fast fourier transform (IFFT) unit;
Normalizing the IFFT-converted data stream based on the maximum subcarrier number information for each channel and the size of the IFFT-converted data stream through a normalization unit;
Converting the normalized data stream into an analog signal via a digital analog converter;
Reducing, by a normalization reduction unit, the data stream converted into the analog signal based on the maximum number of subcarriers for each channel and the size of the IFFT transformed data stream; And
And transmitting the reduced data stream through a radio frequency (RF) unit.
In the normalizing of the IFFT transformed data stream, the normalization unit performs a normalization operation in inverse proportion to the maximum number of subcarriers per channel and proportional to the size of the IFFT transformed data stream,
Performing a rounding operation to match the size of the data stream to the size of an input port of the digital-to-analog converter based on the following equation,

Z denotes a normalized data stream adjusted to correspond to the input port size of the digital analog converter, y denotes a normalized data stream proportional to the size of the IFFT transformed data stream, and OUT _IFFT is And an output port size of the IFFT unit, and the IN _DAC indicates an input port size of the digital-to-analog converter. The method according to claim 7,
The size of the data stream input to the IFFT unit is different from the size of the input port of the digital analog converter. delete The method according to claim 7,
Normalizing the data stream to be proportional to the size of the IFFT transformed data stream,
Generating a normalized data stream proportional to the size of the IFFT transformed data stream based on the following equation:

The y indicates the normalized data stream, the DS _IFFT indicates a data stream obtained from the IFFT unit, the S _IFFT indicates an input / output port size of the IFFT unit, and N _max indicates a subcarrier for each channel. Indicating a maximum number of nodes. delete The method according to claim 7,
Reducing the data stream,
Generate the reduced data stream based on the following equation,

The DS _RE indicates the reduced data stream, the DS _DAC indicates a data stream output from the digital analog converter, and the S _IFFT indicates an input / output port size of the IFFT unit.

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